No problem - I just want to help you understand the concepts!
For the magnitude of ∆G, if it is too large a difference then interconversion between the two would require a lot of energy, so one of the species would not be readily accessible. You would have to really exaggerate the drawing above for this to be the case, but the energy difference has to be within an reasonable range.
For the mechanism problems, do you mean the other thread you have running on this subforum? I glanced at those, but I will take a closer look if I have a few minutes this afternoon.